Friday, April 13, 2012

Eradication challenges - Gambian Rats in Florida Keys

The original news article that touched off the recent round of multiple pickups by media outlets was a March 24, 2012 Keysnet news article, More huge Gambian rats found on Grassy Key By RYAN McCARTHY. It is no longer available free at the original html link but is available in this downloadable pdf version


After extensive bait trapping and surveillance in 2007 and 2008, state Fish and Wildlife Conservation Commission and U.S. Department of Agriculture officials thought the fight against Gambian giant pouch rats on Grassy Key was over. .....

..... Hardin said another round of trapping is planned for July or August. Some 200 traps are baited primarily with cantaloupe and some peanut butter.

Gambian rats were identified as one of several nonnative invasive predators in the Florida Keys along with feral and free roaming cats. See the February 4, 2012 Feral Cat Blog! Post titled Florida Keys Refuges Feral Cat Removal Update

Previous Feral Cat Blog! Posts on:
Gambian Rats in Florida Keys
USDA Wildlife Services
(scroll down or do an Edit/Search with your browser)

Related reports and articles by Witmer and/or others at the USDA/APHIS/National Wildlife Research Center:
[most recent to earliest]

Attempting to eradicate invasive Gambian giant pouched rats (Cricetomys gambianus) in the United States: lessons learned
GW Witmer… - Island invasives: eradication and management, 2011 -

Evaluating commercially available rodenticide baits for invasive Gambian giant pouched rats (< i> Cricetomys gambianus)
[PDF] from
GW Witmer, NP Snow… - Crop Protection, 2010 - Elsevier

Potential attractants for detecting and removing invading Gambian giant pouched rats (Cricetomys gambianus)
[PDF] from
GW Witmer, NP Snow… - Pest management science, 2010 - Wiley Online Library

Identifying Effective Attractants and Rodenticide Baits for Gambian Giant Pouched Rats
G Witmer, NP Snow… - 2010
and presented at the 2010 24th Vertebrate Pest Conference

Challenges and Unique Solutions to Rodent Eradication in Florida.
G Witmer, J Eisemann, P Hall, ML Avery… - 2010 -

The path to eradication of the Gambian giant pouched rat in Florida
[PDF] from
R Engeman, GW Witmer, JB Bourassa, JW Woolard… - 2007 -

Rapid assessment for a new invasive species threat: the case of the Gambian giant pouched rat in Florida
R Engeman, JW Woolard, ND Perry, G Witmer… - Wildlife Research, 2006 - CSIRO

New invasive species in southern Florida: Gambian rat (Cricetomys gambianus)
[PDF] from
ND Perry, B Hanson, W Hobgood, RL Lopez… - Journal of Mammalogy, 2006 - BioOne

USDA >> APHIS >> Wildlife Services >> National Wildlife Research Center NWRC)
Economic Research of Wildlife-Caused Agricultural, Public Health, and Natural Resource Impacts

PROJECT GOAL: Quantify the benefits and costs of NWRC products and Wildlife Services activities that aim to mitigate the impacts of wildlife diseases, wildlife damage to agriculture and natural resources, and wildlife risks to public health/safety.
Project Accomplishments 2006--Monitoring and Tracking:
Gambian Giant Pouched Rats in the Florida Keys
The Gambian giant pouched rat (GGPR) has become an invasive species of concern for the State of Florida. An NWRC researcher worked with Florida WS in 2006 to develop information for planning the species’ eradication from Grassy and Crawl Keys, where it is currently established. A pilot eradication campaign on Crawl Key, employing population monitoring methods developed by NWRC, was carried out in spring of 2006.
Recent camera surveys indicated no GGPR survival on Crawl Key following Hurricane Wilma and the pilot eradication effort. As a result, eradication efforts will now focus on the primary population on Grassy Key. The first step in the eradication process will be to monitor Grassy Key using a camera-indexing methodology cooperatively developed by NWRC and WS Operations personnel. This setup will determine current GGPR distributions and relative abundances throughout the island. Subsequent steps this fall will include the construction and deployment of bait stations especially designed to exclude native species. Bait-station density will be based on the results of the camera survey, with a higher density of bait stations in areas where GGPRs are found. Prebaiting will be done at all bait stations with nontoxic bait to acclimate GGPRs prior to using toxic bait.
The researcher has also been working with economists from the U.S. Department of Interior’s U.S. Geological Survey who are attempting to model this invasive species' impacts should it escape the Keys and become established on the mainland. Work has focused on developing methods to place monetary values on imperiled natural resources, such as rare species and habitats. GGPRs likely would negatively impact agriculture through direct crop losses, contamination of harvested crops, reduced marketability of damaged produce, and contamination and consumption of livestock feed. GGPRs also could negatively impact populations of some threatened and endangered species, especially the endangered Key Largo woodrat, the Key Largo cotton mouse, and the Lower Keys marsh rabbit. GGPRs also have been associated with a variety of pathogenic diseases that could be spread to humans, livestock, or other wildlife.
[above article no longer available at this link: ]